TW202334352A - Silicone adhesive, adhesive sheet and double-sided adhesive sheet - Google Patents

Abstract

The present invention provides a silicone adhesive which contains a modified cyclodextrin. It is preferable that the modified cyclodextrin is at least one of a modified [beta]-cyclodextrin and a modified [gamma]-cyclodextrin. It is also preferable that the modified cyclodextrin is a cyclodextrin that is modified with an acyl group. It is preferable that this silicone adhesive is an addition reaction-type silicone adhesive. This silicone adhesive enables good separation of a release sheet.

Description

Silicone adhesives, adhesive sheets and double-sided adhesive sheets

The present invention relates to a silicone adhesive, an adhesive sheet and a double-sided adhesive sheet using the silicone adhesive.

Various types of adhesive sheets for joining components face-to-face have been known from the past, and a substrate-less double-sided adhesive sheet is known as one type of adhesive sheet. Generally speaking, base-less double-sided adhesive sheets are made by laminating a light-peel film with a relatively low peeling force on the adhesive layer on both sides of an adhesive layer that does not have a base material that serves as the core material. The peeling force of this adhesive layer is relatively high and is formed by a heavy peeling film.

In the above-mentioned double-sided adhesive sheet without a base material, the light release film is first peeled off, and one side of the exposed adhesive layer is adhered to a component. Then, the re-release film is peeled off, and the other side of the exposed adhesive layer is bonded to other components, thereby bonding the components face to face.

However, a problem with base-less double-sided adhesive sheets is that when the light release film is peeled off, the adhesive layer that should be left on the heavy release film side may be pulled by the light release film and follow the peeling of the light release film. Undesirable phenomenon (so-called adhesion).

In order to prevent the peeling failure as described above, the difference in peeling force between the heavy peeling film and the light peeling film has been conventionally increased (for example, see Patent Document 1). [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 7-041736

[Problem to be solved by the invention]

However, when the adhesive layer of the adhesive sheet is formed of a silicone-based adhesive, if a release film that is peeled off with a silicone-based release agent is used, the affinity between the silicones will be high and the peeling force will increase. The above-mentioned peeling failure will occur more significantly.

Therefore, in an adhesive sheet using a silicone-based adhesive, a release film subjected to release treatment with a fluorine-based release agent is usually used. However, there is a problem in that the production cost increases because the release film subjected to release treatment using a fluorine-based release agent is expensive. Therefore, there is a need for an adhesive sheet, particularly a base-less double-sided adhesive sheet, which can use a film that has not undergone the above-mentioned release treatment as a release film.

The present invention has been made in view of such actual circumstances, and an object thereof is to provide a silicone-based adhesive, an adhesive sheet, and a double-sided adhesive sheet that enable the release sheet to be peeled off satisfactorily. [Means used to solve problems]

In order to achieve the above object, first, the present invention provides a silicone-based adhesive containing modified cyclodextrin (Invention 1).

In the above-mentioned invention (Invention 1), by containing modified cyclodextrin, the surface roughness of the adhesive layer formed of the above-mentioned silicone-based adhesive becomes larger. Therefore, the contact area with the release sheet laminated on the adhesive layer becomes smaller, and when the release sheet is peeled off from the adhesive layer, the release sheet can be peeled off satisfactorily. That is, when the release sheet is peeled off, the adhesive layer does not follow the release sheet, and the occurrence of peeling defects such as sticking can be suppressed.

In the above invention (Invention 1), it is preferable that the modified cyclodextrin is at least one of modified β-cyclodextrin and modified γ-cyclodextrin (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the modified cyclodextrin is a cyclodextrin modified with a acyl group (Invention 3).

Among the above inventions (Inventions 1 to 3), an addition reaction type silicone-based adhesive (Invention 4) is preferred.

Secondly, the present invention provides an adhesive sheet having at least an adhesive layer, characterized in that the adhesive layer is formed of the silicone adhesive (Inventions 1 to 4) (Invention 5).

In the above invention (Invention 5), it is preferable that the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more (Invention 6).

Third, the present invention provides a double-sided adhesive sheet, which is provided with an adhesive layer, a first release sheet laminated on one side of the adhesive layer, and a first release sheet laminated on the other side of the adhesive layer. The double-sided adhesive sheet of the second release sheet is characterized in that the adhesive layer is formed of the silicone adhesive (Inventions 1 to 4) (Invention 7).

In the above invention (Invention 7), the arithmetic mean roughness (Ra) of the surface of the adhesive layer exposed by peeling off the first release sheet or the second release sheet is preferably 4 nm or more (Invention 8).

In the above-mentioned inventions (Inventions 7 and 8), it is preferable that the first release sheet and the second release sheet are plastic films that have not been subjected to release processing (Invention 9). [Invention effect]

According to the silicone-based adhesive agent, adhesive sheet and double-sided adhesive sheet of the present invention, the release sheet can be peeled off satisfactorily.

Hereinafter, embodiments of the present invention will be described. [Silicone adhesive] The silicone-based adhesive according to one embodiment of the present invention is a silicone-based adhesive containing modified cyclodextrin. By containing this modified cyclodextrin, the surface roughness of the adhesive layer formed by the silicone-based adhesive increases. Specifically, the arithmetic mean roughness (Ra) is 4 nm or more. Therefore, the contact area with the release sheet laminated on the adhesive layer becomes smaller, and when the release sheet is peeled off from the adhesive layer, the release sheet can be peeled off satisfactorily. That is, when the release sheet is peeled off, the adhesive layer does not follow the release sheet, and the occurrence of peeling defects such as sticking can be suppressed.

Even if the peeling sheet is a plastic film without peeling treatment, the above effect can be achieved. Therefore, there is no need to use a release sheet subjected to release treatment with a fluorine-based release agent, and the manufacturing cost can be reduced. Furthermore, the above effects can be achieved even when there is no double-sided adhesive sheet as a base material. Specifically, when peeling off one side of the plastic film from the base-less double-sided adhesive sheet in which the above-mentioned adhesive layer is sandwiched by two pieces of plastic film that has not been peeled off, no peeling defects such as sticking will occur. , peel off the above plastic film well.

Here, if a general coating method is used, the surface roughness of the adhesive layer formed from the silicone-based adhesive of this embodiment will increase as described above after coating. Such surface roughness can be maintained even after laminating a release sheet on the adhesive layer and peeling off the release sheet. Furthermore, even after the release sheet to which the silicone-based adhesive is applied is peeled off from the adhesive layer formed thereon, the above-mentioned surface roughness can be maintained.

The silicone-based adhesive according to this embodiment specifically contains a silicone-based adhesive main agent and modified cyclodextrin.

1. Silicone adhesive agent The silicone adhesive main agent in this embodiment may be a condensation type silicone adhesive or an addition reaction type silicone adhesive, from the viewpoint of compatibility with modified cyclodextrin, processability, etc. , the addition reaction type silicone adhesive is preferred.

The addition reaction type silicone adhesive preferably contains a first polydimethylsiloxane having at least two alkenyl groups in one molecule and a second polydimethylsiloxane having at least two hydrogenated silyl groups in one molecule. Addition reaction type silicone resin and silicone resin obtained from siloxane.

Examples of the alkenyl group contained in the first polydimethylsiloxane include vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, and octene. Monovalent hydrocarbon groups such as vinyl groups, among which vinyl groups are particularly preferred.

The alkenyl group content (the ratio of the number of alkenyl groups relative to the number of methyl groups bonded to silicon atoms) in the first polydimethylsiloxane is preferably 0.005 to 0.1 mol%, especially 0.01～0.05 mol% is preferred. The alkenyl group preferably exists at both ends of the molecular chain, but may also exist in the side chain. One molecule of the first polydimethylsiloxane contains at least two alkenyl groups. Furthermore, if the content of the alkenyl groups is within the above range, a cross-linked structure with high cross-link density can be formed and adhesive force can be obtained. An adhesive layer with an excellent balance between peelability and peelability.

The degree of polymerization (number of siloxane bonds) of the first polydimethylsiloxane is preferably 200 to 5,000, especially 500 to 3,000. Furthermore, the content of hydrogenated silyl groups in the second polydimethylsiloxane is preferably 2 to 300 per molecule, particularly preferably 4 to 200. The degree of polymerization of the second polydimethylsiloxane is preferably 50 to 2,000, particularly preferably 100 to 1,500. In addition, the blending ratio of the second polydimethylsiloxane relative to 100 parts by mass of the first polydimethylsiloxane is preferably 0.01 to 20 parts by mass, and particularly preferably 0.1 to 10 parts by mass. If the content of each functional group and the blending ratio of the second polydimethylsiloxane to the first polydimethylsiloxane are within the above range, then the first polydimethylsiloxane and the second polydimethylsiloxane will be The addition reaction of methylsiloxane proceeds favorably.

Moreover, it is preferable that the first polydimethylsiloxane does not have a hydrogenated silyl group, and the second polydimethylsiloxane does not have an alkenyl group.

As the silicone resin, for example, a resin composed of an M unit as a monofunctional siloxane unit [(CH ₃ ) ₃ SiO _1/2 ] and a Q unit as a tetrafunctional siloxane unit [SiO _4/2 ] can be used. Formed MQ resin. The molar ratio of M unit/Q unit is preferably 0.6 to 1.7. This silicone resin has the function of imparting adhesiveness to the silicone-based adhesive.

Relative to 100 parts by mass of the addition reaction type silicone resin, the blending amount of the silicone resin is preferably 1 to 200 parts by mass, more preferably 5 to 120 parts by mass, and especially 10 to 80 parts by mass. More preferably, it is 20 to 40 parts by mass. This can achieve a good balance between the adhesive force and the peelability of the release sheet.

The above-mentioned addition reaction type silicone adhesive preferably contains a catalyst. The catalyst is not particularly limited as long as it can cure the addition reaction type silicone resin (addition reaction of the first polydimethylsiloxane and the second polydimethylsiloxane). Among them, Platinum group metal compounds are preferred. Examples of platinum group metal compounds include fine particulate platinum, fine particulate platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, and rhodium. wait. By containing such a catalyst, the curing reaction of the addition reaction type silicone resin can be performed more efficiently.

The proportion of platinum relative to 100 parts by mass of the catalyst for the addition reaction type silicone resin is preferably 0.01 to 3 parts by mass, particularly 0.05 to 2 parts by mass, and further preferably 0.1 to 1 part by mass. good. This can achieve a good balance between the adhesive force and the peelability of the release sheet.

The above-mentioned addition reaction type silicone adhesive may contain, in addition to the above-mentioned components, various additives such as cross-linking agents, reaction inhibitors, colorants, and adhesion improving agents.

2. Modified cyclodextrin In the modified cyclodextrin of this embodiment, at least part of the hydroxyl groups of the cyclodextrin is substituted with other functional groups.

Generally, cyclodextrins are known to have five or more glucose structural units. The cyclodextrin as the skeleton of the modified cyclodextrin in this embodiment may be a cyclodextrin having 5 glucose constituent units, an α-cyclodextrin having 6 glucose constituent units, or a cyclodextrin having a glucose constituent unit. β-cyclodextrin with 7 units may also be γ-cyclodextrin with 8 glucose units. Among them, the modified cyclodextrin in this embodiment is a modified β-cyclodextrin (modified β-cyclodextrin) from the viewpoint of improving the surface roughness of the adhesive layer as described above. It is preferable that at least one kind of modified γ-cyclodextrin (modified γ-cyclodextrin) is used.

In the modified cyclodextrin of the present embodiment, examples of the functional group of the modified cyclodextrin (functional group in which a hydroxyl group is substituted) include, for example, alkoxy groups such as methoxy group and ethoxy group, and acetyl group. Wait and wait. Among these, from the viewpoint of improving the surface roughness of the adhesive layer as described above, a acyl group is preferred, and an acetyl group is particularly preferred.

The degree of modification of the modified cyclodextrin in this embodiment is preferably greater than 2.5, particularly preferably 2.7 or more, and further preferably 2.8 or more. On the other hand, the upper limit of the degree of modification is not particularly limited, but may be 3.0 or less, particularly 2.99 or less, and further may be 2.98 or less. In addition, the degree of modification of modified cyclodextrin in this specification refers to the number of hydroxyl groups substituted by other functional groups per glucose structural unit. Therefore, if all three hydroxyl groups in one glucose structural unit are substituted, the degree of modification is 3.0.

In the silicone-based adhesive agent of this embodiment, one type of modified cyclodextrin may be used alone, or two or more types may be used in combination.

The content of modified cyclodextrin in the silicone-based adhesive of this embodiment is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and further preferably 1% by mass or more. Quality % or more is preferred. Thereby, the surface roughness of the adhesive layer can be effectively improved. Furthermore, the content of modified cyclodextrin in the silicone-based adhesive of this embodiment is preferably 30 mass% or less, more preferably 20 mass% or less, and particularly preferably 15 mass% or less. Furthermore, it is preferably 10% by mass or less. Thereby, the silicone-based adhesive agent of this embodiment can easily exhibit a desired adhesive force and also can easily exhibit a desired releasability.

[adhesive sheet] FIG. 1 shows a cross-sectional view of an adhesive sheet 1 according to an embodiment of the present invention. As shown in FIG. 1 , the adhesive sheet 1 of this embodiment includes an adhesive layer 11 , a base material 12 laminated on one side of the adhesive layer 11 , and a substrate 12 laminated on the other side of the adhesive layer 11 . Peel off sheet 13.

1. Components (1) Adhesive layer The adhesive layer 11 is formed of the silicone adhesive of the above embodiment. The thickness of the adhesive layer 11 is preferably 1 to 1000 μm, more preferably 3 to 500 μm, especially 5 to 100 μm, and further preferably 10 to 50 μm, of which 15 to 35 μm is the preferred thickness. good. By setting the thickness of the adhesive layer 11 within the above range, a good balance can be achieved between the adhesive force and the peelability of the release sheet 13 .

The arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the peeling sheet 13 side is preferably 4 nm or more, more preferably 6 nm or more, especially 7 nm or more, and further preferably 8 nm. , of which 9 nm or above is preferred. Thereby, the peeling sheet 13 can be peeled off favorably from the adhesive layer 11 . The arithmetic mean roughness (Ra) as large as mentioned above can be obtained by applying the silicone-based adhesive of the above-mentioned embodiment by a normal method.

Furthermore, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the peeling sheet 13 side is preferably 100 nm or less, preferably 80 nm or less, especially 60 nm or less, and further preferably 40 nm or less. The following is preferred, with 20 nm or less being preferred. This makes it easier for the adhesive layer 11 to exhibit desired adhesive force. In addition, the details of the method for measuring the arithmetic mean roughness (Ra) of the surface of the adhesive layer in this specification are as described in the test examples described later.

(2)Substrate The base material 12 in this embodiment is not particularly limited, and any material used as a base material of a general adhesive sheet can be used. Examples include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyurethane films, and polyethylene films. Polypropylene film, cellulose film such as triacetyl cellulose, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl acetate copolymer film, polystyrene film, polycarbonate film, Plastic films such as acrylic resin films, norbornene resin films, cycloolefin resin films, etc.; plastic sheets formed from the above resins; woven or non-woven fabrics using fibers such as rayon, acrylic, polyester, etc.; synthetic paper; high-grade Papers such as paper, cellophane, impregnated paper, coated paper, etc.; metal bodies such as aluminum and copper; foams such as polyurethane foam and polyethylene foam; laminates of two or more of the above Board etc.

Moreover, the base material 12 may be what can be peeled off from the adhesive layer 11 (for example, a release sheet). When the base material 12 is a release sheet, the adhesive sheet 1 of this embodiment becomes a double-sided adhesive sheet to be described later.

The thickness of the base material 12 varies depending on the type, but is preferably 5 to 300 μm, more preferably 10 to 200 μm, and particularly preferably 15 to 100 μm.

(3) Peel-off sheet In this embodiment, a plastic film is preferably used as the release sheet 13 . Examples of the plastic film include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polyvinyl chloride, chlorine Ethylene copolymer, polyvinyl acetate, ethylene vinyl acetate, ionomer resin, ethylene/(meth)acrylate copolymer, polyurethane, polystyrene, polycarbonate, polyimide, fluorine Plastic film made of resin, etc. These plastic films can be a single layer or a multi-layer of two or more layers of the same or different types. Furthermore, these plastic films can be uniaxially stretched or biaxially stretched. Among them, polyester film is preferred, and polyethylene terephthalate film is particularly preferred. Polyethylene terephthalate film does not easily generate dust during processing, use, etc., so it can not only effectively prevent coating defects caused by dust, etc., but is also relatively cheap and can help To reduce production costs.

From the viewpoint of being able to be peeled off from the adhesive layer 11 well, the plastic film is preferably a plastic film that has not been peeled off. In the case of using a plastic film that has not been subjected to peeling treatment, since peeling processing is not required, the material (release agent) used can be reduced, which contributes to the reduction of production costs. In particular, because it can use resources less wastefully and become one of the environmentally friendly technologies and production methods, it can contribute to the achievement of the Sustainable Development Goals (SDGs). However, a release agent other than a silicone-based release agent may also be used. For example, a plastic film that has been peeled off with a fluorine-based release agent may be used.

The thickness of the release sheet 13 is preferably 5 to 300 μm, more preferably 10 to 200 μm, especially 15 to 100 μm, and further preferably 20 to 50 μm, from the viewpoint of peelability, operability, etc. Better.

2. Manufacturing method The manufacturing method of the adhesive sheet 1 of this embodiment is not specifically limited. As an example of manufacturing the adhesive sheet 1 , an adhesive coating liquid containing the above-mentioned silicone adhesive and a diluent if necessary is applied to the base material 12 and then dried and solidified to form the adhesive layer 11 .

Coating of the adhesive coating liquid can be carried out by common methods, for example, it can be carried out by rod coating, blade coating, roller coating, blade coating, die coating, gravure coating. To spread the law.

The diluent is not particularly limited, and various diluents can be used. For example, hydrocarbon compounds such as toluene, hexane, and heptane, acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and mixtures thereof can be used.

When the silicone adhesive is an addition reaction type silicone adhesive, it is preferable to thermally cure the applied adhesive coating liquid. In this case, the heating temperature is preferably 80 to 180°C, and the heating time is preferably about 30 to 240 seconds.

After the adhesive layer 11 is formed as described above, the release sheet 13 is bonded to the adhesive layer 11 to obtain the adhesive sheet 1 .

Even by the normal coating method as described above, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the peeling sheet 13 side increases to 4 nm or more. Furthermore, this arithmetic mean roughness (Ra) can be maintained even after the release sheet 13 is laminated on the adhesive layer 12 and peeled off. By increasing the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 in this way, when the peeling sheet 13 is peeled off from the adhesive layer 11, it can be peeled off favorably.

[Double-sided adhesive sheet] FIG. 2 shows a cross-sectional view of the double-sided adhesive sheet 2 according to an embodiment of the present invention. As shown in FIG. 2 , the double-sided adhesive sheet 2 of this embodiment includes an adhesive layer 11 , a first release sheet 21 laminated on one side of the adhesive layer 11 , and a first release sheet 21 laminated on the other side of the adhesive layer 11 . The second peeling piece 22 on the surface.

In this embodiment, as an example, the second release sheet 22 is used as the object to be coated with the silicone-based adhesive coating liquid constituting the adhesive layer 11 , and the first release sheet 21 is used as the object to be adhered to. However, the present invention is not limited thereto.

1. Components (1) Adhesive layer The adhesive layer 11 is formed of the silicone adhesive of the above embodiment. The thickness of the adhesive layer 11 is the same as the thickness of the adhesive layer 11 of the adhesive sheet 1 .

The arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the first release sheet 21 side is the same as the arithmetic mean roughness (Ra) of the surface of the adhesive sheet 1 on the release sheet 13 side. Thereby, the first peeling sheet 21 can be successfully peeled off from the adhesive layer 11 on the second peeling sheet 22, and the occurrence of peeling defects such as blocking can be suppressed.

On the other hand, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the second release sheet 22 side is preferably 4 nm or more, more preferably 4.5 nm or more, and particularly preferably 5 nm or more. Furthermore, 5.5 nm or more is preferred. Thereby, the 2nd release sheet 22 can be peeled off favorably from the adhesive layer 11 (attached to an adherend).

Furthermore, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the second release sheet 22 side is preferably 100 nm or less, more preferably 80 nm or less, and particularly preferably 60 nm or less. Further, 40 nm or less is more preferred, and 20 nm or less is particularly preferred. This makes it easier for the adhesive layer 11 to exhibit desired adhesive force.

The adhesive layer 11 in the double-sided adhesive sheet 2 of this embodiment preferably does not have a base material as a core material. That is, the double-sided adhesive sheet 2 of this embodiment is a double-sided adhesive sheet without a base material. Better. Double-sided adhesive sheets without a base material, especially when peeling off the release sheet, tend to cause peeling defects such as sticking. However, the double-sided adhesive sheet 2 of this embodiment can suppress the occurrence of such peeling defects.

(2) First release sheet and second release sheet The materials and thickness of the first release sheet 21 and the second release sheet 22 are the same as the release sheet 13 of the adhesive sheet 1 mentioned above.

In the double-sided adhesive sheet 2 of this embodiment, it is preferable that the peeling force of the second release sheet 22 on the adhesive layer 11 is greater than the peeling force of the first release sheet 21 on the adhesive layer 11 . Thereby, when the first release sheet 21 is peeled off from the adhesive layer 11 , it is possible to effectively suppress the occurrence of adhesion in which the adhesive layer 11 is pulled by the first release sheet 21 and peeled off from the second release sheet 22 . The coating liquid of the silicone-based adhesive constituting the adhesive layer 11 is applied to the second release sheet 22, and the first release sheet 21 is bonded to the formed adhesive layer 11, whereby the above-mentioned method can be achieved. Adjust the peeling force accordingly.

In this embodiment, the peeling force of the first release sheet 21 on the adhesive layer 11 is preferably 1 to 200 mN/25mm, more preferably 5 to 150 mN/25mm, especially 10 to 100 mN/25m. The best is 15~70 mN/25 mm, and the best is 20~50 mN/25 mm. Thereby, when first peeling off the first peeling sheet 21 from the adhesive layer 11 , the first peeling sheet 21 can be easily peeled off without any problem. Furthermore, it is possible to prevent the first peeling sheet 21 from being peeled off from the adhesive layer 11 unexpectedly. In addition, the details of the peel force measurement method in this specification are as described in the test examples described later.

In this embodiment, the peeling force of the second release sheet 22 on the adhesive layer 11 is preferably 5 to 300 mN/25mm, more preferably 10 to 210 mN/25mm, especially 15 to 110 mN/25mm. For better results, 25 to 80 mN/25mm is more preferred, and 30 to 60 mN/25mm is more preferred. Thereby, when the first release sheet 21 is peeled off from the adhesive layer 11 , the adhesive layer 11 can be effectively prevented from being peeled off from the second release sheet 22 . Furthermore, the second peeling sheet 22 can be easily peeled off from the adhesive layer 11 attached to the adherend without any problem.

The difference in peeling force between the first peeling sheet 21 and the second peeling sheet 22 is preferably 1 to 150 mN/25mm, more preferably 5 to 100 mN/25mm, especially 7 to 80 mN/25mm. Further, 10-50 mN/25 mm is better, and 12-30 mN/25 mm is the best. Thereby, the first peeling sheet 21 can be peeled off from the adhesive layer 11 without any problem such as sticking.

2. Manufacturing method of double-sided adhesive sheet As a preferred manufacturing example of the double-sided adhesive sheet 2 of this embodiment, the adhesive coating liquid containing the above-mentioned silicone adhesive and a desired diluent can be applied to the second release sheet 22, and then It is dried and solidified to form the agent layer 11 . Specifically, the adhesive layer 11 can be formed in the same manner as the adhesive sheet 1 described above. After the adhesive layer 11 is formed, the first release sheet 21 is bonded to the adhesive layer 11 to obtain the double-sided adhesive sheet 2 .

By using the silicone-based adhesive described above, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the first release sheet 21 side can be increased to 4 nm or more even with the conventional coating method. Furthermore, this arithmetic mean roughness (Ra) can be maintained even after the first release sheet 21 is laminated on the adhesive layer 22 and the first release sheet 21 is peeled off. By increasing the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 in this way, when the first release sheet 21 is peeled off from the adhesive layer 11, the adhesive layer 11 will not follow the first release sheet 21. Since it is peeled off from the second peeling sheet 22, the occurrence of peeling defects such as sticking can be suppressed.

[Another embodiment] An adhesive sheet according to another embodiment of the present invention at least has an adhesive layer, wherein the adhesive layer is formed of a silicone adhesive, and the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more. . The adhesive sheet of this embodiment may be a double-sided adhesive sheet or a double-sided adhesive sheet without a base material.

By setting the arithmetic mean roughness (Ra) of the surface of the adhesive layer to a roughness of 4 nm or more, the contact area with the release sheet laminated on the adhesive layer becomes smaller. When the release sheet is removed from the above-mentioned When the adhesive layer is peeled off, it can be peeled off well. That is, the above-mentioned adhesive layer does not follow or adhere to the peeling sheet, and can prevent peeling defects such as adhesion from occurring.

The silicone adhesive constituting the adhesive layer is preferably the silicone adhesive of the above embodiment, but is not limited thereto.

The structure other than the above is the same as that of the adhesive sheet 1 or the double-sided adhesive sheet 2 mentioned above.

The embodiments described above are described for easier understanding of the present invention and are not intended to limit the present invention. Therefore, each element disclosed in the above-mentioned embodiment is intended to include all design changes and equivalents falling within the technical scope of the present invention.

For example, the adhesive layer 11 may have a core material.

In addition, in this specification, when "X～Y" (where X and Y are arbitrary numbers) are written, unless otherwise stated, it means "above X and below Y", and also includes "preferably It means "bigger than X" or "preferably smaller than Y". Furthermore, when "X or more" (where X is an arbitrary number) is written, it means "preferably larger than ), unless otherwise stated, it means "preferably smaller than Y". [Example]

In the following, the present invention will be explained in more detail through examples, but the scope of the present invention is not limited by these examples.

[Preparation Example 1] 1.8 g of β-cyclodextrin (manufactured by Nacalai Tesque) and 47 mg of p-toluenesulfonic acid monohydrate as a catalyst were added to 8.5 ml of isopropylene acetate as a solvent, and the mixture was reacted at 70° C. for 16 hours. The reaction solution was distilled off under reduced pressure, and the obtained solid was washed with 10% by mass sodium carbonate aqueous solution, extracted with chloroform, and recrystallized with acetone to obtain 2.5 g of acetylated β-cyclodextrin as a white solid. .

A part of the obtained acetylated β-cyclodextrin was dissolved in deuterated chloroform, and analyzed by ¹ H-NMR (trade name "Nuclear Magnetic Resonance Equipment JNM-LA400/WB" manufactured by JEOL Ltd.). The analysis result is the integration of the peak derived from the proton connected to the first carbon of the glucose ring at around 5.1 ppm in the ¹ H-NMR spectrum and the peak derived from the acetyl group at around 2.1 ppm. Ratio, the calculated degree of modification is 2.98.

[Preparation Example 2] 2 g of γ-cyclodextrin (manufactured by Nacalai Tesque) and 47 mg of p-toluenesulfonic acid monohydrate as a catalyst were added to 8.5 ml of isopropylene acetate as a solvent, and the mixture was reacted at 70° C. for 16 hours. The reaction solution was distilled off under reduced pressure, and the obtained solid was washed with 10% by mass sodium carbonate aqueous solution, extracted with chloroform, and recrystallized with acetone to obtain 2.5 g of acetylated γ-cyclodextrin as a white solid. .

A part of the obtained acetylated γ-cyclodextrin was dissolved in deuterated chloroform, and analyzed by ¹ H-NMR (trade name "Nuclear Magnetic Resonance Equipment JNM-LA400/WB" manufactured by JEOL Ltd.). The analysis result is the integration of the peak derived from the proton connected to the first carbon of the glucose ring at around 5.1 ppm in the ¹ H-NMR spectrum and the peak derived from the acetyl group at around 2.1 ppm. Ratio, the calculated degree of modification is 2.97.

[Example 1] 1. Preparation of adhesive coating liquid Add 100 parts by mass of addition reaction type silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., "KS-847H") (solid content conversion; the same applies below), silicone resin (manufactured by Dow Corning Toray Co., Ltd., "SD-4584") ) 30 parts by mass, 0.5 parts by mass of platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., "SRX 212 CATALYST"), 3 parts by mass of acetylated γ-cyclodextrin prepared in Preparation Example 2 and diluent Mix methyl ethyl ketone and use this as an adhesive coating liquid.

2. Manufacturing of double-sided adhesive sheets The adhesive coating liquid obtained in step 1 above was applied to a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "DIAFOIL T100- 50S", thickness 50 μm) on one side. Then, the coating layer was heat-treated at 120° C. for 2 minutes to form a coating layer with a thickness of 25 μm.

After that, the adhesive layer on the second release sheet obtained above was combined with a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "DIAFOIL T100-50S", thickness 50 μm) as the first release sheet. ), thereby manufacturing a double-sided adhesive sheet with an adhesive layer of thickness 25 μm, that is, a seamless adhesive sheet formed by the structure of the first release sheet/adhesive layer (thickness: 25 μm)/the second release sheet. The base material is double-sided adhesive sheet. In addition, the thickness of the adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by Teclock Corporation, product name "PG-02") in accordance with JIS K7130.

[Examples 2 to 3, Comparative Example 1] A base-less double-sided adhesive sheet was produced in the same manner as in Example 1 except that the types and amounts of components of the adhesive coating liquid were changed as shown in Table 1.

[Reference example 1] As the first release sheet, a release sheet in which one side of a polyethylene terephthalate film was peeled off with a silicone-based release agent (product name "SP-PET751130" manufactured by Lintec Corporation) was used. A substrate-free double-sided adhesive sheet was produced in the same manner as in Example 1, except that the release-treated surface of the first release sheet was bonded to the adhesive layer on the second release sheet.

[Test Example 1] (Measurement of surface roughness) The second release sheet side of the base-less double-sided adhesive sheet produced in Examples, Comparative Examples, and Reference Examples was fixed to the glass plate using double-sided tape. After that, the first release sheet is peeled off from the base-material-free double-sided adhesive sheet, and an optical interference type surface shape observation device (manufactured by Veeco Japan, product name " NT1100"), observe in PSI mode at 50 times magnification, and measure the arithmetic mean roughness (Ra) (nm). At this time, 10 images in the range of 120 μm × 120 μm were obtained from the surface shape image, the arithmetic mean roughness (Ra) (nm) was measured in each image, and the average of these values was regarded as the arithmetic mean. Roughness (Ra) (nm). The results are shown in Table 2.

In addition, the arithmetic mean roughness (Ra) (nm) of the surface of the adhesive layer on the second release sheet side was also measured in the same manner as above. The results are shown in Table 2.

[Test Example 2] (Measurement of Peeling Force) The substrate-free double-sided adhesive sheet produced in the Examples, Comparative Examples and Reference Examples was cut into a width of 25 mm and a length of 100 mm. Thereafter, the second release sheet was peeled off, and the exposed adhesive layer was bonded to alkali-free glass (product name "Eagle XG" manufactured by Corning Incorporated) to obtain a measurement sample.

For the obtained measurement sample, a tensile testing machine (manufactured by Orientec, product name "TENSILON") was used to peel the first peeling sheet from the adhesive layer at a peeling speed of 300 mm/min and a peeling angle of 180 degrees. The peeling force (N/25mm) of the first peeling sheet was measured. Measurement conditions other than the above are measured in accordance with JIS Z0237:2009. The results are shown in Table 2. Furthermore, in Reference Example 1, the adhesion between the first peeling sheet and the adhesive layer was so strong that peeling occurred between the adhesive layer and the alkali-free glass, and the relationship between the first peeling sheet and the adhesive layer could not be measured. the peeling force between them.

In addition, the peeling force (mN/25mm) of the 2nd peeling sheet was also measured in the same manner as above. The results are shown in Table 2. Furthermore, in Comparative Example 1, the adhesion between the second peeling sheet and the adhesive layer was so strong that peeling occurred between the adhesive layer and the alkali-free glass, and the relationship between the second peeling sheet and the adhesive layer could not be measured. the peeling force between them.

[Test Example 3] (Evaluation of Transferability) 99 parts by mass of n-butyl acrylate and 1 part by mass of 4-hydroxybutyl acrylate were copolymerized by a solution polymerization method to prepare an acrylate polymer (weight average molecular weight: 1.5 million).

The weight average molecular weight (Mw) mentioned above is a weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement). ＜Measurement conditions＞ ・GPC measurement device: Made by Tosoh Corporation, HLC-8020 ・GPC string (passed in the following order): manufactured by Tosoh Corporation TSK guard column HXL-H TSK gel GMHXL (x 2) TSK gel G2000HXL ・Measurement solvent: Tetrahydrofuran ・Measuring temperature: 40℃

100 parts by mass of the (meth)acrylate polymer obtained above (solid content conversion value, the same applies below) was mixed with trimethylolpropane-modified polypylenedimethyl diisocyanate as the cross-linking agent (B). (manufactured by Soken Chemical Co., Ltd., trade name "TD-75") 0.2 parts by mass was mixed, thoroughly stirred, and diluted with methyl ethyl ketone to obtain an acrylic adhesive coating liquid.

The obtained acrylic adhesive coating liquid was applied to a glass plate and then heat-treated at 130° C. for 1 minute to form an acrylic adhesive layer with a thickness of 25 μm.

The second peeling sheet was peeled off from the base-less double-sided adhesive sheet produced in the Examples, Comparative Examples and Reference Examples, and the exposed adhesive layer (silicone adhesive layer) was bonded to the above-mentioned acrylic adhesive layer. . After that, it was left to stand at room temperature for 24 hours and used as a sample.

A tensile testing machine (manufactured by Orientec, product name "TENSILON") was used to peel the first peeling piece from the silicone adhesive layer of the above sample at a peeling speed of 300 mm/min and a peeling angle of 90 degrees. At this time, if the state of the silicone adhesive layer being transferred to the acrylic adhesive layer can be maintained and the first release sheet can be peeled off without any problem, the transferability is evaluated as good (○); If a peeling sheet is peeled off from the acrylic adhesive layer at the same time, it is evaluated as poor transferability (×). The results are shown in Table 2.

[Table 1] Silicone adhesive composition (mass parts) Adhesive layer thickness (μm) Addition reaction silicone resin Silicone resin Platinum catalyst Acetylated β-cyclodextrin Acetylated γ-cyclodextrin Example 1 100 30 0.5 - 3 25 Example 2 100 30 0.5 5 - 25 Example 3 100 - 0.5 - 3 25 Comparative example 1 100 30 0.5 - - 25 Reference example 1 100 30 0.5 - 3 25

[Table 2] Arithmetic mean roughness Ra (nm) Peeling force (mN/25mm) Transferability evaluation First peeling piece side Second peeling piece side First peeling piece side Second peeling piece side Example 1 11.9 6.8 41 54 〇 Example 2 10.7 5.7 45 58 〇 Example 3 9.6 6.1 twenty two 38 〇 Comparative example 1 2.9 - 120 Unable to measure × Reference example 1 11.9 9.4 Unable to measure 54 ×

As can be seen from Table 2, the substrate-free double-sided adhesive sheet produced in the Example has good transferability of the adhesive layer (silicone adhesive layer), and the adhesive layer formed of polyethylene terephthalate film The release sheet has excellent releasability. [Industrial Applicability]

The silicone adhesive, adhesive sheet and double-sided adhesive sheet of the present invention are suitable for lamination, for example, in curved displays, curved glass, functional/decorative films, etc.

1: Adhesive sheet 11: Adhesive layer 12:Substrate 13: peel off piece 2:Double-sided adhesive sheet 21: First peeling piece 22: Second peeling piece

[Fig. 1] is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention. [Fig. 2] is a cross-sectional view of a double-sided adhesive sheet according to an embodiment of the present invention.

1: Adhesive sheet

11: Adhesive layer

12:Substrate

13: peel off piece

Claims (9)

A silicone-based adhesive containing modified cyclodextrin. The silicone adhesive according to claim 1, wherein the modified cyclodextrin is at least one of modified β-cyclodextrin and modified γ-cyclodextrin. The silicone adhesive according to claim 1, wherein the modified cyclodextrin is a cyclodextrin modified with a acyl group. The silicone adhesive according to claim 1 is an addition reaction type silicone adhesive. An adhesive sheet having at least an adhesive layer, characterized in that the adhesive layer is formed of the silicone adhesive as described in any one of claims 1 to 4. The adhesive sheet according to claim 5, wherein the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more. A double-sided adhesive sheet, which has: adhesive layer, the first peeling sheet laminated on one side of the adhesive layer, and A double-sided adhesive sheet with a second release sheet laminated on the other side of the adhesive layer, It is characterized in that the above-mentioned adhesive layer is formed of the silicone adhesive as described in any one of claims 1 to 4. The double-sided adhesive sheet according to claim 7, wherein the arithmetic mean roughness (Ra) of the surface of the adhesive layer exposed by peeling off the first release sheet or the second release sheet is 4 nm or more. The double-sided adhesive sheet according to claim 7, wherein the first peeling sheet and the second peeling sheet are plastic films that have not been peeled off.

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